1. Field of the Invention
The present invention relates to a solar cell module having an improved terminal box structure.
2. Related Background Art
Various installation places and methods for a flexible thin film solar cell module are available. FIG. 10 shows an example of a conventional flexible solar cell module. Referring to FIG. 10, reference numeral 1001 denotes an installing surface; 1002, photovoltaic elements; 1003, a cable; and 1004, a terminal box. The photovoltaic elements 1002 are provided with an edge cover 1005 serving as an edge protective member for protecting their edges. The two ends of the edge protective member are connected to each other with an edge cover connecting member (an fixing member) 1006 and are simultaneously fixed to the solar cell module.
This terminal extracting method utilizing a terminal box is generally used for a roof solar cell module, a ground solar cell module, and the like in addition to a roofing material integrated solar cell module. When a solar cell module is to be installed by adhering it to an installing surface, since the terminal box is a projection, it must be fixed to the light-incident side so that it will not interfere with the adhesion surface. FIG. 10 shows an example wherein the terminal box is fixed to the light-incident side in this manner.
When, however, a solar cell module is adhered to a building in this state, the terminal box portion tends to peel. Since the solar cell module requires weather resistance, the cover member of the terminal box adhesion surface often uses a fluoroplastic, leading to an insufficient reliability at the terminal box adhesion portion. Since the terminal box projects from the surface, it can be easily damaged.
FIGS. 9A to 9C show a case wherein, as a countermeasure against terminal box peeling, a solar cell module is fixed to the automobile roof by extracting a terminal without using a terminal box. FIG. 9A is a schematic view of the solar cell module, FIG. 9B is a sectional view of the module taken along the line 9B--9B of FIG. 9A, and FIG. 9C is a sectional view of the module taken along the line 9C--9C of FIG. 9A.
Referring to FIGS. 9A to 9C, reference numeral 901 denotes an installing surface; 902, photovoltaic elements; 903, a cable; 904, an upper cover member; 905, a lower cover member; 906, a filler; 907, an in-cable copper wire; and 908, a solder portion, respectively. As a countermeasure against terminal box peeling, the terminal is extracted not through a terminal box, but is directly extracted from the end portion of the module by connecting a lead-in cable directly to the photovoltaic element, as shown in FIG. 9B.
At the terminal extraction portion in the end portion of the solar cell module, since the cover member partly constituting the solar cell module is adhered with a stress, the upper cover member 904 and filler 906, or the lower cover member 905 and filler 906 gradually peel from each other over a long-term use. At the terminal extraction portion, the cable 903 is directly inserted in the filler 906. The cable 903 and filler 906 may also undesirably peel from each other.
In FIG. 9B, the cable 903 is inserted in the filler 906 directly from the end portion of the solar cell module. The cable has a copper wire in its insulating cover member. The interface between the insulated cover member and the inner copper wire tends to pass moisture, that has entered the cable, through it. With the structure of FIG. 9B, when the moisture should enter the cable over a long-term use, it tends to enter the solar cell module along the cable. In this case, the long-term reliability may suffer.
When a terminal box is arranged on the lower surface of the solar cell module, the workability is poor when installing the solar cell module to the roof of a building structure or automobile.